Wireless receiving system



July 7, 1931. c. T. JAcBs WIRELESS RECEIVING SYSTEM Filed April 412; 1928 s n" SQNN .Ng SQN\ m M im, lh. #Q im M .m M V o y o W Z A/,m 5 l U m u Irx r\ m f.\ f lvlicll, Pme. .MQ U A. V rx. Nh v Nb N. k mb hU s m. $.11 Fw nu .o M lr QQ 5M.

` Patented July 7, 1931 i fUNiTED stares CHARLES T. JACOBS, OF :EAST ORANGE, NEW JERSEY, ASSIGI'IOR TO SPLITDGPLF RADIO CORPORATION, OF NEWARK, JERSEY WIRELESS RECEIVING? SYSTEM Y Application :tiled April 12,

This invention relates to a system for receiving and converting Wireless sound Waves so as tol properly actuate a receiverv or loud speaker. y

- My improvement in such a receiving system resides in means pertaining to or utilizing and controlling regeneration in the vacuum tube used as a detector, said detectorbeing preceded by at least one stage of radio frequency amplification, and also in means for controlling the volume of the sound Waves delivered to the receiving instrument per se. A stilly further object of my invention is to provide ready'means for converting the receiving setrfrom one having regenerative action to one Without such action,`but having single control over the volume. Another object of my invention is to provide means for reducing the proportion of the radio frequency component of the detector plate current so as to modify the regenerative action. In order to illustrate my invention, I have chosen to illustrate itin connection With a series of vacuum tubes having filament, grid and plate elements vinterlinked by suitable transformers, in Which preferably the input circuits ofthe tubes preceding the detector tube are'tuned, an'd Y Figure l of the vdrawings accompanying this specification, illustrates one form of receiving system in which I have chosen to show myA invention. Figure 2 .shows a modified formvof the invention.A In the drawings, l,

2, 3,-and 4, are radio frequency transformers,

and 5 and 6 are audio frequency transformers. Transformer l has one end of its primary ll connected to earth E, and has taps T to Which the antenna A may be selectively connected t-o different number of turns in the primary ll for Well-known reasons.

Associated with the secondary i2, is a variv able condenser 13 for tuning the circuit which is connected tothe grid Gr of the first tube lO, .Which tube hasthe usual filament F and plate P. The primary 2l of the transformer 2 is connected to the plate P of tube 10, while the secondary 22 With its tuning condenser 23, is connected to a cont-rolling resistance 24 to the grid oftube 2O.` The resistances 24- and 34 H128. Serial No. 269,337.

are used for the purpose of suppressing the tendencies of tubes and 30 to oscillate.

In similar manner, the primary Bl and secondary 32 of transformer 3 with tuning condenser 33, are used to interlink tube 2O to tube 30, the resistance similar to 24 being used in the grid circuitof the tube 30. Tube 4() is used as a detector. rid leali resistance 44 with its associated condenser 45 of low capacity, Whose functions are old and Well known, is connected to the grid of this tube and to the secondary 42 and timing condenser 43 of transformer Associated with the primary 4l of the transformer 4, is a resistance or potentiometer 35, having its extremities X and Y connected across or parallel with the Winding 4l.

The movable contact Z of the potentiometer is connected to one terminal of the switch S, the other terminal of which is connected to the extremity X of the potentiometer. Movable contact Z is also connected with a condenser 46, the opposite terminal of which is connected to the plate P of the detector tube 40. v

Tube 5() is associated with an'audio frequency transformer 5, Whose primary 5l is connected to the source of current supply for the plate circuit of detect-or 4O, While the secondary 52 is connected to the input side of the tube 50. Preferably associated or connected across the secondary 52 of the transformer 5, is a high resistance 54, which is used for the purpose of suppressing the tend encies of the audio frequency amplifier to oscillate.

Connected to the tube 50, is primary 6l of transformer 6, the secondary 62 of Which is connected to the input side of tube GO. Associated With the filament of the detector tube 40, is a fixed center tapped resistance 4S, having the cent-er tap grounded for the purpose of reducing the excessive hum from this tube, it being understood as indicated by the designations, on the terminal post that alternating current is used to supply this receiving system with energizing power.

Connected across the filament of tube GO, is a similar resistance 64 for the purpose of establishing the electrical center of said lilafil ment v To the central point of this resistance, is connected a biasing resistance 65, thev opposite end of which is grounded, thereby pro-l I r`duci'ngla bias for the'tubeO, due tothe plate current of 'this tube Yfion/ing through therenected to,4 the' plate circuit in the manner shown. 71' is afixed center tapped resistance,

and 72 a potentiometer, both being `placed Vacross the filament tubes l0,` 20,39, and 50, forl the purpose Yof establishing theelectrical center of these filaments.l 7 3 is a biasing resist-.

' ance fortubes l0, 20,3(),and 50, Whichbias".y Y

" hzed for the purpose off rechicin'g#the'pro-v Y is produced by the plate currents of "these V10, 20, y30, and'G tubes Vflowing through the resistance 73, A bypass condenser 8O is'used in connection'with the resistance 7 3,' While a-bypass condenser 8l is placed across the'plate supply for the tubes 'y My inventionresides primarily in the arrangement involving the potentiometer 35 andthe condenser 46-With van'auxiliary condenser'47y Which :may in; some cases .be used. rPhe potentiometer 'has a resistance of they Vorderfof tenthousandfoh'ms, and 'as has been pointed out, is'connectedacross the primary Y '41 of ythe radio frequency"transfor1ner4, the

.secondary ofivhichfleads into ythe grid circuit of'detector tube 40.V Ihave found the con"- denser 46Tto give excellent results Whenof Vthe order of :,002 microfarads-cap'acity'.

' l101,"tentiometerresistance 35.

. of radio frequency component coming.

tive effect."

` Y Y In operation,I .when the movable Contact Z .f'offpotentiometer is. v connected-to` point' Y, a

portion of the radio frequency component of the detector rplate circuit passes through con-A denseri 46; vand theninparallel through the ance 3K5V iswvery high inV comparisonwith the reactance ofwinding 411; a large-proportion throughthecondenser 46, passesthrough the Winding 4l`-of thetransformer4,and under thisfcondition, gives the maximum'regenera- As the movable contact Z ofthe potentiometer 'is moved Atoward the point X, the less f Y' Will j'be the amount of l"regenerative current -flowingjthroughthe- Winding 41,y and hence theamountof feed-back or regenerative ac` j f tion is reduced', until the movable contact Z'V reaches the point ',X, when; no feed-'back 'or re-k generative action takes place. It'isto be understoodthatthe primary purpose'of regen-v eration is torv 'enable' the .reception of signals l`too Weakto be received'yvithout regenergdsion,v

as the incoming signals become strongenf the need for feed-'back or regeneration is correspondingly reducedjand the 'regenerative action is very simplycontrolled bythe poten,

tiometer 'action as'described Idiave found VYthatgthe same potentiometer which controls the regenerative' act1on','rmay 1 the potentiometer,Vv :and kWinding 4l, thereby,rv

cutting 'off th'eregenerative' action and'alloyving the 'potentionie't'erto be operated for sim-k ple volume contnol, as thelpotentiometer then becomes a variable resistance vassociated With the primary 4l of thetra-nsformer 4. f Y

In some cases al condenser 47'may be Auti of the detector plate current Whichwillflow through. theA condenserA 46 Yto theV potenti ometer as described. Thisadditionalcontrol Y due to vcondenser 47 governed' .f by' the size f of the condenser '47, and.' deL sire d, this controlKV action may be' brou ghtf into use by a switch 49.- Vlt is to'be understood-that condenser 47fis not necessary-5V but'is often: times helpfulin obtaining-smootherlregeni erativev action; 1 Y

lnV Figure 2 I have-jshovvnl aymo'difiefd'arlrangement for obtainingcontrol ofthe regen# erative vaction 1 previously referredi to a'sWell -`as 'volume control. ByVY this! latterfarranges- I ment, the v4switch S- is 'eliminated and the point' .e VeXtendingfrom the resistance 35 'to .v the condenser 46`is Xedffs'o-thatthe resistv ance lyingb'etweenlthe poi-nte andthe poi-nty yisv preferably of theV orderifojf'aboutOd f vohms.r4 The point Vmis'. connected to a .movl ableV -contact 1 36 which may be moved` over" theenti'reVV length off thek resistance 35'.

- v When the movable contact 36 is -at th'evpoint 'a or between zand y, no-reg'eneration occurs,

lportion of the radio frequency'. component p as the `feedfback currents passingl through condenser 46, WillYtheniloW-directlyfthrough the s ection-.`,e-36 Y,of resistancetto 4radio frequency ground, the''same f' as AFigure li k".lhesectimi E36-gis always inshunttothe?V primary 4l` ofthe transformer '4land by var" riation of the resistance value; of the section 1 E56-Jy, the control of the volume :of thes'et" former 4, and in Vhen. the movable contactdris. on'the opi-1i v positeside ofthe tap-2' frointheend y, as i, indicated in v'Figure 2,' the; feedback currents` flowing, throughcondenser j.46,' ydivide f be,- tween the vtwo paths--onee-andvgtheother 1.a*g/ primary 41,'k so that variationfof-,the

value of the section .fa- 36 causesavariation". `of' the ,quantity of the: feed-back currents;y passingthrough the primary 41of the Qtra'ns-- Assuming that the iscontrolled l by a, suitable'membersuch'as a rotatin-glknob,"

it Will be seen that a sinoothfincrease fiofin;`

obtained by turning the control knob, whereby the contact 36 is caused to travel along the length of the resistance 35. Hence, the active working length of said resistance is that part between the point y and the contact 36 wherever it may be located along the length of the resistance 35.

In Figure l, the active length of the resistance is from y to w when the switch S is open,and this corresponds to the condition when 36 is at the extremityrof 35 opposite to the point y. The operation of the movable contact 36 modifies the regenerative feature and eliminates it entirely when moved as Vabove explained, the same as the operation of switch S eliminates the regenerative feature entirely.

O f course it is obvious that contact a and contact 36 may both be variable if desired,

` f and other'changes are of course contemplated, as long as these changes do not depart from the spirit of my invention and the scope of the appended claims.

Having thus described my invention, what l I claim is:

1. In a receiving system for wireless waves which includes; at least one stage of radio frequency amplification including its associated vacuum tube and at least one stage of audio frequency amplification including its associated vacuum tube and a detector tube operatively connected on its input side with the radio frequency amplification stage and on its output side with said audio stage;

i means for utilizing and controlling regeneration in the detector tube including a potentiometer having its extremities connected in parallel with some part of the radio frequency stage connected to the input of the detector tube and a condenser connected between the plate of the detector tube and the movable contact member of the potentiometer.

. 2. In a receiving system for wireless waves,

a detector tube provided with a coupling device having an input circuit leading to the detector; means for utilizing and controlling regeneration in the detector tube including a potentiometer having its extremities connect- "l ed in parallel with some part of the radio frevice having an input circuit leading to the detector, means for utilizing and controlling regeneration in the detector tube including a potentiometer having its extremities connected in parallel with at least some ,portion of the coupling device feeding into the detector grid kcircuit and a condenser connected between the plate vof the detector tube and the movable contact member of the potentiometer, and means for eliminating the regenerative feature when not desired and utilizing the potentiometer for volume control of the receiving system. v

Ll. In a receiving system for wireless waves, adetector tube provided with a coupling device having an input circuitleading to the'detector, means for utilizing and controlling regeneration in the detector tube including a potentiometer having its extremities connected in parallel with at least some portion of the coupling device feeding into the detector grid circuit and a condenser connected between the plate of the detector tube and the movable contact member of the potentiometer, and means for eliminating the regenerative feature when not desired and utilizing the potentiometer for volume control of the receiving system, said means consisting of a switch for establishing a short circuit from the low potential side of the potentiometer to the movable contact thereof.

5. In a receiving system for wireless waves detector tube provided with a, coupling'device having an input circuit leading to the detector; means for utilizing and controllingy regeneration in the detector tube includinga potentiometer having its extremities connected in parallel with some part of the coupling device connected to the input of the detector tube and a condenser connected between the plate ofthe detector tube and the movable contact member of the potentiometer, said means also including a movable device capable of effecting a shunt circuit around that part of the potentiometer between the point m and the movable contact.

6. In a receiving system for wireless waves, a detector tube provided with a coupling device having an input circuit leading to the detector; means for utilizing and controlling regeneration in the detector tube including a. resistance having at least one end connected with some part of the radio frequency stage connected to the input of the detector tube, a condenser connected between the plate circuit of the detector tube and some point on the resistance and means for connecting at least said point on the resistance to another part of the coupling device as and for the purposes described.

7. In a receiving system for wireless waves, means for utilizing and controlling regeneration and volume therein including, a potentiometer for regulating both, and means for eliminating the regenerative feature lover at least some portion of the potentiometer when not desired, and utilizing at least the re- 

